check engine light JAGUAR XJ6 1997 2.G Owner's Manual

rebuilt engine or short block, some rebuilders
will not warranty their engines unless the
radiator has been professionally flushed. Also,
we don’t recommend overhauling the oil
pump - always refit a new one when an engine
is rebuilt.
Before beginning the engine overhaul, read
through the entire procedure to familiarise
yourself with the scope and requirements of
the job. Overhauling an engine isn’t difficult,
but it is time-consuming. Plan on the vehicle
being tied up for a minimum of two weeks,
especially if parts must be taken to an
automotive machine workshop for repair or
reconditioning. Check on availability of parts
and make sure that any necessary special
tools and equipment are obtained in advance.
Most work can be done with typical hand
tools, although a number of precision
measuring tools are required for inspecting
parts to determine if they must be renewed.
Often an automotive machine workshop will
handle the inspection of parts and offer
advice concerning reconditioning and
renewal. Note:Always wait until the engine
has been completely dismantled and all
components, especially the engine block,
have been inspected before deciding what
service and repair operations must be
performed by an automotive machine
workshop. Since the engine block’s condition
will be the major factor to consider when
determining whether to overhaul the original
engine or buy a rebuilt one, never purchase
parts or have machine work done on other
components until the engine block has been
thoroughly inspected. As a general rule, time
is the primary cost of an overhaul, so it
doesn’t pay to refit worn or substandard
parts.
If it turns out that a number of major
components are beyond reconditioning, it
may be cost effective to buy a factory-rebuilt
engine from a Jaguar dealership.
As a final note, to ensure maximum life and
minimum trouble from a rebuilt engine,
everything must be assembled with care in a
spotlessly-clean environment.
3 Vacuum gauge
diagnostic checks
2
A vacuum gauge provides valuable
information about what is going on in the
engine at a low cost. You can check for worn
rings or cylinder walls, leaking cylinder head or
intake manifold gaskets, incorrect carburettor
adjustments, restricted exhaust, stuck or
burned valves, weak valve springs, improper
ignition or valve timing and ignition problems.
Unfortunately, vacuum gauge readings are
easy to misinterpret, so they should be used
with other tests to confirm the diagnosis.
Both the absolute readings and the rate of
needle movement are important for accurate
interpretation. Most gauges measure vacuumin inches of mercury (in-Hg). As vacuum
increases (or atmospheric pressure decreases),
the reading will decrease. Also, for every
1000 foot increase in elevation above sea level;
the gauge readings will decrease about one
inch of mercury.
Connect the vacuum gauge directly to
intake manifold vacuum, not to ported (above
the throttle plate) vacuum (see illustration).
Be sure no hoses are left disconnected during
the test or false readings will result.
Before you begin the test, allow the engine
to warm up completely. Block the wheels and
set the handbrake. With the transmission in
Park, start the engine and allow it to run at
normal idle speed.
Warning: Carefully inspect the
fan blades for cracks or damage
before starting the engine. Keep
your hands and the vacuum
tester clear of the fan and do not stand in
front of the vehicle or in line with the fan
when the engine is running.
Read the vacuum gauge; an average,
healthy engine should normally produce
between 17 and 22 inches of vacuum with a
fairly steady needle.
Refer to the following vacuum gauge
readings and what they indicate about the
engines condition:
1A low steady reading usually indicates a
leaking gasket between the intake manifold
and carburettor or throttle body, a leaky
vacuum hose, late ignition timing or incorrect
camshaft timing. Check ignition timing with a
timing light and eliminate all other possible
causes, utilising the tests provided in this
Chapter before you remove the timing belt
cover to check the timing marks.
2If the reading is three to eight inches below
normal and it fluctuates at that low reading,
suspect an intake manifold gasket leak at an
intake port or a faulty injector.
3If the needle has regular drops of about two
to four inches at a steady rate the valves are
probably leaking. Perform a compression or
leak-down test to confirm this.
4An irregular drop or down-flick of the
needle can be caused by a sticking valve or
an ignition misfire. Perform a compression or
leak-down test and read the spark plugs.5A rapid vibration of about four in-Hg
vibration at idle combined with exhaust
smoke indicates worn valve guides. Perform a
leak-down test to confirm this. If the rapid
vibration occurs with an increase in engine
speed, check for a leaking intake manifold
gasket or cylinder head gasket, weak valve
springs, burned valves or ignition misfire.
6A slight fluctuation, say one inch up and
down, may mean ignition problems. Check all
the usual tune-up items and, if necessary, run
the engine on an ignition analyser.
7If there is a large fluctuation, perform a
compression or leak-down test to look for a
weak or dead cylinder or a blown cylinder
head gasket.
8If the needle moves slowly through a wide
range, check for a clogged PCV system,
incorrect idle fuel mixture, throttle body or
intake manifold gasket leaks.
9Check for a slow return after revving the
engine by quickly snapping the throttle open
until the engine reaches about 2,500 rpm and
let it shut. Normally the reading should drop to
near zero, rise above normal idle reading
(about 5 in.-Hg over) and then return to the
previous idle reading. If the vacuum returns
slowly and doesn’t peak when the throttle is
snapped shut, the rings may be worn. If there
is a long delay, look for a restricted exhaust
system (often the silencer or catalytic
converter). An easy way to check this is to
temporarily disconnect the exhaust ahead of
the suspected part and redo the test.
4 Cylinder compression check
2
1A compression check will tell you what
mechanical condition the upper end (pistons,
rings, valves, cylinder head gasket) of your
engine is in. Specifically, it can tell you if the
compression is down due to leakage caused
by worn piston rings, defective valves and
seats or a blown cylinder head gasket. Note:
The engine must be at normal operating
temperature and the battery must be fully
charged for this check.
2Begin by cleaning the area around the
spark plugs before you remove them
(compressed air should be used, if available,
otherwise a small brush or even a bicycle tyre
pump will work). The idea is to prevent dirt
from getting into the cylinders as the
compression check is being done.
3Remove all of the spark plugs from the
engine (see Chapter 1).
4Block the throttle wide open.
5Detach the coil wire from the centre of the
distributor cap and ground it on the engine
block. Use a jumper wire with alligator clips on
each end to ensure a good earth. Also,
remove the fuel pump relay (see Chapter 4) to
disable the fuel pump during the compression
test.
Engine removal and overhaul procedures 2B•3
2B
3.4 The vacuum gauge is easily attached
to a port on the intake manifold, and can
tell a lot about an engine’s state of tune
3261 Jaguar XJ6

6Refit the compression gauge in the spark
plug hole (see illustration).
7Crank the engine over at least seven
compression strokes and watch the gauge.
The compression should build up quickly in a
healthy engine. Low compression on the first
stroke, followed by gradually increasing
pressure on successive strokes, indicates
worn piston rings. A low compression reading
on the first stroke, which doesn’t build up
during successive strokes, indicates leaking
valves or a blown cylinder head gasket (a
cracked cylinder head could also be the
cause). Deposits on the undersides of the
valve heads can also cause low compression.
Record the highest gauge reading obtained.
8Repeat the procedure for the remaining
cylinders and compare the results to this
Chapter’s Specifications.
9Add some engine oil (about three squirts
from a plunger-type oil can) to each cylinder,
through the spark plug hole, and repeat the
test.
10If the compression increases after the oil
is added, the piston rings are definitely worn.
If the compression doesn’t increase
significantly, the leakage is occurring at the
valves or cylinder head gasket. Leakage past
the valves may be caused by burned valve
seats and/or faces or warped, cracked or bent
valves.
11If two adjacent cylinders have equally low
compression, there’s a strong possibility that
the cylinder head gasket between them is
blown. The appearance of coolant in the
combustion chambers or the crankcase
would verify this condition.
12If one cylinder is 20 percent lower than the
others, and the engine has a slightly rough
idle, a worn exhaust lobe on the camshaft
could be the cause.
13If the compression is unusually high, the
combustion chambers are probably coated
with carbon deposits. If that’s the case, the
cylinder head(s) should be removed and
decarbonised.
14If compression is way down or varies
greatly between cylinders, it would be a goodidea to have a leak-down test performed by
an automotive repair workshop. This test will
pinpoint exactly where the leakage is
occurring and how severe it is.
5 Engine removal-
methods and precautions
If you’ve decided that an engine must be
removed for overhaul or major repair work,
several preliminary steps should be taken.
Locating a suitable place to work is
extremely important. Adequate work space,
along with storage space for the vehicle, will
be needed. If a workshop or garage isn’t
available, at the very least a flat, level, clean
work surface made of concrete or asphalt is
required.
Cleaning the engine compartment and
engine before beginning the removal
procedure will help keep tools clean and
organised.
An engine hoist or A-frame will also be
necessary. Make sure the equipment is rated
in excess of the combined weight of the
engine and transmission. Safety is of primary
importance, considering the potential hazards
involved in lifting the engine out of the vehicle.
If the engine is being removed by a novice,
a helper should be available. Advice and aid
from someone more experienced would also
be helpful. There are many instances when
one person cannot simultaneously perform all
of the operations required when lifting the
engine out of the vehicle.
Plan the operation ahead of time. Arrange
for or obtain all of the tools and equipment
you’ll need prior to beginning the job. Some of
the equipment necessary to perform engine
removal and refitting safely and with relative
ease are (in addition to an engine hoist) a
heavy duty trolley jack, complete sets of
spanners and sockets as described in the
front of this manual, wooden blocks and
plenty of rags and cleaning solvent for
mopping up spilled oil, coolant and petrol. If
the hoist must be rented, make sure that you
arrange for it in advance and perform all of the
operations possible without it beforehand.
This will save you money and time.
Plan for the vehicle to be out of use for
quite a while. A machine workshop will be
required to perform some of the work which
the do-it-yourselfer can’t accomplish without
special equipment. These shops often have a
busy schedule, so it would be a good idea to
consult them before removing the engine in
order to accurately estimate the amount of
time required to rebuild or repair components
that may need work.
Always be extremely careful when removing
and refitting the engine. Serious injury can
result from careless actions. Plan ahead, take
your time and a job of this nature, although
major, can be accomplished successfully.
6 Engine- removal and refitting
3
Note:Read through the entire Section before
beginning this procedure. It is recommended
to remove the engine and transmission from
the top as a unit, then separate the engine
from the transmission on the workshop floor. If
the transmission is not being serviced, it is
possible to leave the transmission in the
vehicle and remove the engine from the top by
itself, by removing the crankshaft damper and
tilting up the front end of the engine for
clearance,but access to the upper
bellhousing bolts is only practical when the
rear transmission mount and driveshaft have
been removed and the transmission is angled
down with a trolley jack.
Removal
1Relieve the fuel system pressure (see
Chapter 4).
2Disconnect the battery negative cable.
Caution: If the stereo in your vehicle is
equipped with an anti-theft system, make
sure you have the correct activation code
before disconnecting the battery.
3Place protective covers on the wings and
cowl and remove the bonnet (see Chapter 11).
4Remove the battery and battery tray.
5Remove the air cleaner assembly (see
Chapter 4).
6Raise the vehicle and support it securely on
axle stands. Drain the cooling system and
engine oil and remove the drivebelts (see
Chapter 1).
7Clearly label, then disconnect all vacuum
lines, coolant and emissions hoses, wiring
harness connectors and earth straps.
Masking tape and/or a touch up paint
applicator work well for marking items (see
illustration). Take instant photos or sketch
the locations of components and brackets.
8Remove the cooling fan(s) and radiator (see
Chapter 3).
9Disconnect the heater hoses.
10Release the residual fuel pressure in the
tank by removing the petrol cap, then detach
the fuel lines connecting the engine to the
chassis (see Chapter 4). Plug or cap all open
fittings.
2B•4 Engine removal and overhaul procedures
4.6 A compression gauge with a threaded
fitting for the spark plug hole is preferred
over the type that requires hand pressure
to maintain the seal - be sure to block
open the throttle valve as far as possible
during the compression check!
6.7 Label both ends of each wire and hose
before disconnecting it
3261 Jaguar XJ6

11Disconnect the throttle linkage,
transmission linkage (and dipstick tube) and
speed control cable, if equipped, from the
engine (see Chapters 4 and 7).
12Refer to Part A of this Chapter and
remove the intake and exhaust manifolds.
13Unbolt the power steering pump (see
Chapter 10). Tie the pump aside without
disconnecting the hoses. Refer to Part A for
removal of the hydraulic pump (if equipped)
from the timing chain cover.
14On air-conditioned models, unbolt the
compressor and set it aside. Do not
disconnect the refrigerant hoses. Note:Wire
the compressor out of the way with a coat
hanger, don’t let the compressor hang on the
hoses.
15Refer to Part A of this Chapter and
remove the drivebelts, water pump pulley and
crankshaft pulley.
16Attach a lifting sling to the engine.
Position a hoist and connect the sling to it.
Take up the slack until there is slight tension
on the hoist.
17With a trolley jack and piece of wood
supporting the bottom of the transmission
sump, refer to Chapter 8 and remove the
driveshaft and rear transmission mount.
Warning: Do not place any part
of your body under the
engine/transmission when it’s
supported only by a hoist or
other lifting device.
18With the hoist taking the weight of the
engine, unbolt the engine mounts (see Part A
of this Chapter).
19Recheck to be sure nothing is still
connecting the engine or transmission to the
vehicle. Disconnect and label anything still
remaining.
20Slowly lift the engine/transmission out of
the vehicle (see illustration). It may be
necessary to pry the mounts away from the
frame brackets.21Move the engine away from the vehicle
and carefully lower the hoist until the
engine/transmission can be set on the floor.
Refer to Chapter 7 and remove the
transmission and converter. Refer to Part A of
this Chapter for removal of the flywheel. With
the flywheel removed, remove the four large
bolts and the transmission adapter plate from
the engine (see illustration).
22Refer to Part A of this Chapter for removal
of the rear main seal retainer plate from the
back of the engine, then lift the engine to a
position where it can be attached to a sturdy
engine stand.
Refitting
23Check the engine/transmission mounts. If
they’re worn or damaged, renew them.
24Attach the hoist and remove the engine
from the stand. Refer to Part A of this Chapter
and renew the rear main seal and retainer
plate, then reattach the transmission adapter
plate and refer to Chapter 7 for mounting the
converter and transmission.
25Carefully lower the engine into the vehicle
with the hoist. An assistant is helpful to guide
the engine clear of accessories in the engine
compartment as the engine is lowered into
place.
26Refit the engine mount bolts and tighten
them securely. Raise the back of the
transmission with the trolley jack and reattach
the transmission mount, driveshaft and shift
linkage.
27Refit the remaining components and
fasteners in the reverse order of removal.
28Add coolant, oil, power steering and
transmission fluids as needed (see Chapter 1).
29Run the engine and check for proper
operation and leaks. Shut off the engine and
recheck the fluid levels.
7 Engine rebuilding
alternatives
The do-it-yourselfer is faced with a number
of options when performing an engine
overhaul. The decision to renew the engine
block, piston/connecting rod assemblies and
crankshaft depends on a number of factors,
with the number one consideration being the
condition of the engine block. Other
considerations are cost, access to machine
workshop facilities, parts availability, time
required to complete the project and the
extent of prior mechanical experience on the
part of the do-it-yourselfer.
Some of the rebuilding alternatives include:
Individual parts- If the inspection
procedures reveal that the engine block and
most engine components are in reusable
condition, purchasing individual parts may be
the most economical alternative. The engine
block, cylinder head, crankshaft, and
piston/connecting rod assemblies should all
be inspected carefully. Even if the engine
block shows little wear, the cylinder bores
should be surface honed.
Short block- A short block consists of an
engine block with a crankshaft and
piston/connecting rod assemblies already
installed. All new bearings are incorporated
and all clearances will be correct. The existing
camshafts, valve train components, cylinder
head and external parts can be bolted to the
short block with little or no machine workshop
work necessary.
Long block- A long block consists of a
short block plus an oil pump, sump, cylinder
head, valve cover, camshaft and valve train
components, timing sprockets and chain or
gears and timing cover. All components are
installed with new bearings, seals and gaskets
Engine removal and overhaul procedures 2B•5
2B
3261 Jaguar XJ6 6.20 Lift the engine high enough to clear the vehicle, tilting it up
at the front to clear the front crossmember, then move it away
and lower the hoist
6.21 With the engine on the floor but still supported by the hoist,
remove the four large bolts (arrowed) and pull off the
transmission adapter plate

2Using a gasket scraper, remove all traces of
gasket material from the engine block. Be very
careful not to nick or gouge the gasket sealing
surfaces.
3Remove the main bearing caps and
separate the bearing inserts from the caps
and the engine block. Tag the bearings,
indicating which cylinder they were removed
from and whether they were in the cap or the
engine block, then set them aside.
4Remove all of the threaded oil gallery plugs
from the engine block. The plugs are usually
very tight - they may have to be drilled out and
the holes retapped. Use new plugs when the
engine is reassembled.
5If the engine is extremely dirty, it should be
taken to an automotive machine workshop to
be steam cleaned or hot tanked.
6After the engine block is returned, clean all
oil holes and oil galleries one more time.
Brushes specifically designed for this purpose
are available at most car accessory outlets.
Flush the passages with warm water until the
water runs clear, dry the engine block
thoroughly and wipe all machined surfaces
with a light, rust preventive oil. If you have
access to compressed air, use it to speed the
drying process and to blow out all the oil
holes and galleries. Warning: Wear eye protection
when using compressed air!
7If the engine block isn’t extremely dirty or
sludged up, you can do an adequate cleaning
job with hot soapy water and a stiff brush.
Take plenty of time and do a thorough job.
Regardless of the cleaning method used, be
sure to clean all oil holes and galleries very
thoroughly, dry the engine block completely
and coat all machined surfaces with light oil.
8The threaded holes in the engine block
must be clean to ensure accurate torque
readings during reassembly. Run the proper
size tap into each of the holes to remove rust,
corrosion, thread sealant or sludge and
restore damaged threads (see illustration). If
possible, use compressed air to clear the
holes of debris produced by this operation.
9Refit the main bearing caps and tighten the
bolts finger tight.
10After coating the sealing surfaces of the
new core plugs with suitable sealant, refit
them in the engine block (see illustration).
Make sure they’re driven in straight and
seated properly or leakage could result.
Special tools are available for this purpose,
but a large socket, with an outside diameter
that will just slip into the core plug, a 1/2-inchdrive extension and a hammer will work just
as well.
11Apply non-hardening sealant (such as
Permatex no. 2 or Teflon pipe sealant) to the
new oil gallery plugs and thread them into the
holes in the engine block. Make sure they’re
tightened securely.
12If the engine isn’t going to be
reassembled right away, cover it with a large
plastic trash bag to keep it clean.
16 Engine block- inspection
2
1Before the engine block is inspected, it
should be cleaned as described in Section 15.
2Visually check the engine block for cracks,
rust and corrosion (see illustration 10.12).
Look for stripped threads in the threaded
holes. It’s also a good idea to have the engine
block checked for hidden cracks by an
automotive machine workshop that has the
special equipment to do this type of work,
especially if the vehicle had a history of
overheating or using coolant. If defects are
found, have the engine block repaired, if
possible, or renewed. If the top of the engine
block has been eroded by coolant leakage
and the erosion is near the cylinder bores, the
engine block must be renewed.
3Check the cylinder bores for scuffing and
scoring.
4Check the cylinders for taper and out-of-
round conditions as follows (see illustrations):
5Measure the diameter of each cylinder at
the top (just under the ridge area), centre and
bottom of the cylinder bore, parallel to the
crankshaft axis.
6Next, measure each cylinder’s diameter at
the same three locations perpendicular to the
crankshaft axis.
7The taper of each cylinder is the difference
between the bore diameter at the top of the
cylinder and the diameter at the bottom. The
out-of-round specification of the cylinder bore
Engine removal and overhaul procedures 2B•11
2B
16.4a Measure the diameter of each
cylinder at 90° to engine centreline (A), and
parallel to engine centreline (B) - out-of-
round is the difference between A and B;
taper is the difference between A and B at
the top of the cylinder and A and B at the
bottom of the cylinder16.4b The ability to “feel” when the
telescoping gauge is at the correct point
will be developed over time, so work
slowly and repeat the check until you’re
satisfied that the bore measurement is
accurate
3261 Jaguar XJ6
15.8 All bolt holes in the engine block -
particularly the main bearing cap and
cylinder head bolt holes - should be
cleaned and restored with a tap (remove
debris from holes after this is done)15.10 A large socket on an extension can
be used to drive the new core plugs into
the bores
16.4c The gauge is then measured with a
micrometer to determine the bore size

is the difference between the parallel and
perpendicular readings. Compare your results
to this Chapter’s Specifications.
8If the cylinder walls are badly scuffed or
scored, or if they’re out-of-round or tapered
beyond the limits given in this Chapter’s
Specifications, have the engine block rebored
and honed at an automotive machine
workshop. If a rebore is done, oversize
pistons and rings will be required.
9Using a precision straightedge and feeler
gauge, check the engine block deck (the
surface that mates with the cylinder head) for
distortion (see illustration 10.13). If it’s
distorted beyond the specified limit, it can be
resurfaced by an automotive machine
workshop.
10If the cylinders are in reasonably good
condition and not worn to the outside of the
limits, and if the piston-to-cylinder clearances
can be maintained properly, then they don’t
have to be rebored. Honing is all that’s
necessary (refer to Section 17).
17 Cylinder honing
3
1Prior to engine reassembly, the cylinder
bores must be honed so the new piston rings
will seat correctly and provide the best
possible combustion chamber seal. Note:If
you don’t have the tools or don’t want to
tackle the honing operation, most automotive
machine shops will do it for a reasonable fee.
2Before honing the cylinders, refit the main
bearing caps (without bearing inserts) and
tighten the bolts to the specified torque.
3Two types of cylinder hones are commonly
available - the flex hone or “bottle brush” type
and the more traditional surfacing hone with
spring-loaded stones. Both will do the job, but
for the less-experienced mechanic the “bottle
brush” hone will probably be easier to use.
You’ll also need some paraffin or honing oil,
rags and a variable-speed electric drill motor.
The drill motor should be operated at a
steady, slow speed. Proceed as follows:
a) Mount the hone in the drill motor,
compress the stones and slip it into the
first cylinder (see illustration).
Warning: Be sure to wear safety
goggles or a face shield!
b) Lubricate the cylinder with plenty of
honing oil, turn on the drill and move the
hone up-and-down in the cylinder at a
pace that will produce a fine crosshatch
pattern on the cylinder walls. Ideally, the
crosshatch lines should intersect at
approximately a 60° angle (see
illustration). Be sure to use plenty of
lubricant and don’t take off any more
material than is absolutely necessary to
produce the desired finish. Note:Piston
ring manufacturers may specify a smallercrosshatch angle than the traditional 60° -
read and follow any instructions included
with the new rings.
c) Don’t withdraw the hone from the cylinder
while it’s running. Instead, shut off the drill
and continue moving the hone up-and-
down in the cylinder until it comes to a
complete stop, then compress the stones
and withdraw the hone. If you’re using a
“bottle brush” type hone, stop the drill
motor, then turn the chuck in the normal
direction of rotation while withdrawing the
hone from the cylinder.
d) Wipe the oil out of the cylinder and repeat
the procedure for the remaining cylinders.
4After the honing job is complete, chamfer
the top edges of the cylinder bores with a
small file so the rings won’t catch when the
pistons are installed. Be very careful not to
nick the cylinder walls with the end of the file.
5The entire engine block must be washed
again very thoroughly with warm, soapy water
to remove all traces of the abrasive grit
produced during the honing operation. Note:
The bores can be considered clean when a
lint-free white cloth - dampened with clean
engine oil - used to wipe them out doesn’t
pick up any more honing residue, which will
show up as grey areas on the cloth. Be sure to
run a brush through all oil holes and galleries
and flush them with running water.
6After rinsing, dry the engine block and
apply a coat of light rust preventive oil to all
machined surfaces. Wrap the engine block in
a plastic bag to keep it clean and set it aside
until reassembly.
18 Pistons/connecting rods-
inspection
2
1Before the inspection process can be
carried out, the piston/connecting rod
assemblies must be cleaned and the original
piston rings removed from the pistons. Note:
Always use new piston rings when the engine
is reassembled.
2Using a piston ring refitting tool, carefully
remove the rings from the pistons. Be careful
not to nick or gouge the pistons in the
process.
3Scrape all traces of carbon from the top of
the piston. A hand-held wire brush or a piece
of fine emery cloth can be used once the
majority of the deposits have been scraped
away. Do not, under any circumstances, use a
wire brush mounted in a drill motor to remove
deposits from the pistons. The piston material
is soft and may be eroded away by the wire
brush.
4Use a piston ring groove-cleaning tool to
remove carbon deposits from the ring
grooves. If a tool isn’t available, a piece
broken off the old ring will do the job. Be very
careful to remove only the carbon deposits -
don’t remove any metal and do not nick or
scratch the sides of the ring grooves (see
illustrations).
5Once the deposits have been removed,
clean the piston/connecting rod assemblies
with solvent and dry them with compressed
air (if available). Make sure the oil return holes
2B•12 Engine removal and overhaul procedures
17.3a A “bottle brush” hone will produce
better results if you have never done
cylinder honing before17.3b The cylinder hone should leave a
smooth, crosshatch pattern with the lines
intersecting at approximately a 60° angle
18.4a The piston ring grooves can be
cleaned with a special tool, as shown . . .18.4b . . . or a section of a broken ring
3261 Jaguar XJ6

in the back sides of the ring grooves and the
oil hole in the lower end of each rod are clear.
6If the pistons and cylinder walls aren’t
damaged or worn excessively, and if the
engine block is not rebored, new pistons
won’t be necessary. Normal piston wear
appears as even vertical wear on the piston
thrust surfaces and slight looseness of the top
ring in its groove. New piston rings, however,
should always be used when an engine is
rebuilt.
7Carefully inspect each piston for cracks
around the skirt, at the pin bosses and at the
ring lands.
Caution: Some early 1988 3.6 litre engines
(before engine no. 9D 121113) have
incorrectly-stamped pistons. On these, the
word FRONT is actually stamped on the rear
of the pistons. Correct pistons will have the
cast arrows on the inside of the skirt to your
left when facing the word FRONT.
8Look for scoring and scuffing on the thrust
faces of the skirt, holes in the piston crown
and burned areas at the edge of the crown. If
the skirt is scored or scuffed, the engine may
have been suffering from overheating and/or
abnormal combustion, which caused
excessively high operating temperatures. The
cooling and lubrication systems should be
checked thoroughly. A hole in the piston
crown is an indication that abnormal
combustion (pre-ignition) was occurring.
Burned areas at the edge of the piston crown
are usually evidence of spark knock
(detonation). If any of the above problems
exist, the causes must be corrected or the
damage will occur again. The causes may
include intake air leaks, incorrect air/fuel
mixture, incorrect ignition timing and EGR
system malfunctions.
9Corrosion of the piston, in the form of small
pits, indicates that coolant is leaking into the
combustion chamber and/or the crankcase.
Again, the cause must be corrected or the
problem may persist in the rebuilt engine.
10Measure the piston ring groove clearance
by laying a new piston ring in each ring groove
and slipping a feeler gauge in beside it (see
illustration). Check the clearance at three or
four locations around each groove. Be sure touse the correct ring for each groove - they are
different. If the clearance is greater than that
listed in this Chapter’s Specifications, new
pistons will have to be used.
11Check the piston-to-bore clearance by
measuring the bore (see Section 16) and the
piston diameter. Make sure the pistons and
bores are correctly matched. Measure the
piston across the skirt, at a 90° angle to
the piston pin (see illustration). Subtract the
piston diameter from the bore diameter to
obtain the clearance. If it’s greater than
specified, the engine block will have to be
rebored and new pistons and rings installed.
12Check the piston-to-rod clearance by
twisting the piston and rod in opposite
directions. Any noticeable play indicates
excessive wear, which must be corrected.
13If the pistons must be removed from the
connecting rods for any reason, the rods
should be taken to an automotive machine
workshop, to be checked for bend and twist,
since automotive machine shops have special
equipment for this purpose.
14Check the connecting rods for cracks and
other damage. Temporarily remove the rod
caps, lift out the old bearing inserts, wipe the
connecting rod and cap bearing surfaces
clean and inspect them for nicks, gouges and
scratches. After checking the connecting
rods, renew the old bearings, slip the caps
into place and tighten the nuts finger tight.
Note:If the engine is being rebuilt because of
a connecting rod knock, be sure to refit new
rods.
19 Crankshaft- inspection
3
1Clean the crankshaft with solvent and dry it
with compressed air (if available). Be sure to
clean the oil holes with a stiff brush and flush
them with solvent.
2Check the main and connecting rod bearing
journals for uneven wear, scoring, pits and
cracks.
3Remove all burrs from the crankshaft oil
holes with a stone, file or scraper.4Check the remainder of the crankshaft for
cracks and other damage. It should be
magnafluxed to reveal hidden cracks - an
automotive machine workshop will handle the
procedure.
5Using a micrometer, measure the diameter
of the main and connecting rod journals and
compare the results to this Chapter’s
Specifications (see illustration). By
measuring the diameter at a number of points
around each journal’s circumference, you’ll be
able to determine whether or not the journal is
out-of-round. Take the measurement at each
end of the journal, near the crank throws, to
determine if the journal is tapered. Crankshaft
runout should be checked also, but large V-
blocks and a dial indicator are needed to do it
correctly. If you don’t have the equipment,
have a machine workshop check the runout.
6If the crankshaft journals are damaged,
tapered, out-of-round or worn beyond the
limits given in the Specifications, have the
crankshaft reground by an automotive
machine workshop. Be sure to use the correct
size bearing inserts if the crankshaft is
reconditioned.
7Check the oil seal journals at each end of
the crankshaft for wear and damage. If the
seal has worn a groove in the journal, or if it’s
nicked or scratched, the new seal may leak
when the engine is reassembled. In some
cases, an automotive machine workshop may
be able to repair the journal by pressing on a
thin sleeve. If repair isn’t feasible, a new or
different crankshaft should be installed.
8Refer to Section 20 and examine the main
and big-end bearing inserts.
20 Main and big-end bearings-
inspection and selection
3
Inspection
1Even though the main and big-end bearings
should be replaced with new ones during the
engine overhaul, the old bearings should be
retained for close examination, as they may
Engine removal and overhaul procedures 2B•13
2B
19.5 Measure the diameter of each
crankshaft journal at several points to
detect taper and out-of-round conditions
3261 Jaguar XJ6 18.10 Check the ring groove clearance
with a feeler gauge at several points
around the groove
18.11 Measure the piston diameter at a
90° angle to the piston pin, at the bottom
of the piston pin area - a precision caliper
may be used if a micrometer isn’t available

21 Engine overhaul-
reassembly sequence
1Before beginning engine reassembly, make
sure you have all the necessary new parts,
gaskets and seals as well as the following
items on hand:
Common hand tools
A 1/2-inch drive torque wrench
Piston ring refitting tool
Piston ring compressor
Short lengths of rubber or plastic hose to
fit over connecting rod bolts
Plastigauge
Feeler gauges
A fine-tooth file
New engine oil
Engine assembly lube or moly-base
grease
Gasket sealer
Thread locking compound
Special Jaguar tools:
Engine lifting brackets (18G 1465)
Timing damper simulator (18E 1436)
Camshaft TDC tool (18G 1433)
2In order to save time and avoid problems,
engine reassembly must be done in the
following general order:
Piston rings (Part B)
Crankshaft and main bearings (Part B)
Piston/connecting rod assemblies (Part B)
Rear main (crankshaft) oil seal (Part B)
Auxiliary shaft (Part A)
Timing chains and sprockets (Part A)
Oil pump (Part A)
Timing chain cover (Part A)
Cylinder head and lifters (Part A)
Camshafts (Part A)
Oil pick-up (Part A)
Sump (Part A)
Intake and exhaust manifolds (Part A)
Valve cover (Part A)
Flywheel/driveplate (Part A)
22 Piston rings- refitting
3
1Before refitting the new piston rings, the ring
end gaps must be checked. It’s assumed that
the piston ring groove clearance has been
checked and verified correct (see Section 18).
2Lay out the piston/connecting rod
assemblies and the new ring sets so the ring
sets will be matched with the same piston and
cylinder during the end gap measurement and
engine assembly.
3Insert the top (number one) ring into the first
cylinder and square it up with the cylinder
walls by pushing it in with the top of the piston
(see illustration). The ring should be near the
bottom of the cylinder, at the lower limit of
ring travel.
4To measure the end gap, slip feeler gauges
between the ends of the ring until a gauge
equal to the gap width is found (see
illustration). The feeler gauge should slide
between the ring ends with a slight amount of
drag. Compare the measurement to that
found in this Chapter’s Specifications. If the
gap is larger or smaller than specified,
double-check to make sure you have the
correct rings before proceeding.
5If the gap is too small, it must be enlarged
or the ring ends may come in contact with
each other during engine operation, which
can cause serious damage to the engine. The
end gap can be increased by filing the ring
ends very carefully with a fine file. Mount thefile in a vice equipped with soft jaws, slip the
ring over the file with the ends contacting the
file face and slowly move the ring to remove
material from the ends(see illustration).
Caution: When performing this operation,
file only from the outside in, and after the
correct gap is achieved, deburr the filed
ends of the rings with a fine whetstone.
6Excess end gap isn’t critical unless it’s
greater than Specifications. Again, double-
check to make sure you have the correct rings
for your engine.
7Repeat the procedure for each ring that will
be installed in the first cylinder and for each
ring in the remaining cylinders. Remember to
keep rings, pistons and cylinders matched.
8Once the ring end gaps have been
checked/corrected, the rings can be installed
on the pistons.
9The oil control ring (lowest one on the
piston) is usually installed first. It’s composed
of three separate components. Slip the
spacer/expander into the groove (see
illustration). If an anti-rotation tang is used,
make sure it’s inserted into the drilled hole in
the ring groove. Next, refit the lower side rail.
Don’t use a piston ring refitting tool on the oil
ring side rails, as they may be damaged.
Instead, place one end of the side rail into the
groove between the spacer/expander and the
ring land, hold it firmly in place and slide a
finger around the piston while pushing the rail
into the groove (see illustrations). Next, refit
the upper side rail in the same manner.
10After the three oil ring components have
been installed, check to make sure that both
Engine removal and overhaul procedures 2B•15
2B
22.3 When checking piston ring end gap,
the ring must be square in the cylinder
bore (this is done by pushing the ring down
with the top of a piston as shown)22.4 With the ring square in the cylinder,
measure the end gap with a feeler gauge22.5 If the end gap is too small, clamp a
file in a vice and file the ring ends (from the
outside in only) to enlarge the gap slightly
22.9a Refit the spacer/expander in the oil
control ring groove22.9b DO NOT use a piston ring refitting
tool when refitting the oil ring side rails
3261 Jaguar XJ6

the upper and lower side rails can be turned
smoothly in the ring groove.
11The number two (middle) ring is installed
next. It’s usually stamped with a mark which
must face up, toward the top of the piston.
Note:Always follow the instructions on the
ring package or box - different manufacturers
may require different approaches. Do not mix
up the top and middle rings, as they have
different cross sections.
12Use a piston ring refitting tool and make
sure the ring’s identification mark is facing the
top of the piston, then slip the ring into the
middle groove on the piston (see illustration).
Don’t expand the ring any more than
necessary to slide it over the piston.
13Refit the number one (top) ring in the
same manner. Make sure the mark is facing
up. Be careful not to confuse the number one
and number two rings.
14Repeat the procedure for the remaining
pistons and rings.
23 Crankshaft- refitting and
main bearing oil clearance
check
3
1Crankshaft refitting is the first major step in
engine reassembly. It’s assumed at this point
that the engine block and crankshaft have
been cleaned, inspected and repaired or
reconditioned.
2Position the engine with the bottom facing
up.
3Remove the main bearing cap bolts and lift
out the caps. Lay the caps out in the proper
order.
4If they’re still in place, remove the old
bearing inserts from the engine block and the
main bearing caps. Wipe the main bearing
surfaces of the engine block and caps with a
clean, lint free cloth. They must be kept
spotlessly clean!
Main bearing
oil clearance check
5Clean the back sides of the new main
bearing inserts and lay the bearing half with
the oil groove in each main bearing saddle inthe engine block. Lay the other bearing half
from each bearing set in the corresponding
main bearing cap. Make sure the tab on each
bearing insert fits into the recess in the engine
block or cap. Also, the oil holes in the block
must line up with the oil holes in the bearing
insert.
Caution: Do not hammer the bearings into
place and don’t nick or gouge the bearing
faces. No lubrication should be used at this
time.
6The thrust bearings (washers) must be
installed in the number four main bearing cap
and saddle.
7Clean the faces of the bearings in the
engine block and the crankshaft main bearing
journals with a clean, lint free cloth. Check or
clean the oil holes in the crankshaft, as any
dirt here can go only one way - straight
through the new bearings.
8Once you’re certain the crankshaft is clean,
carefully lay it in position in the main bearings.
9Before the crankshaft can be permanently
installed, the main bearing oil clearance must
be checked.
10Trim several pieces of the appropriate size
Plastigauge (they must be slightly shorter than
the width of the main bearings) and place one
piece on each crankshaft main bearing
journal, parallel with the journal axis (see
illustration).
11Clean the faces of the bearings in the
caps and refit the caps in their respective
positions (don’t mix them up) with the arrows
pointing toward the front of the engine. Don’t
disturb the Plastigauge. Apply a light coat of
oil to the bolt threads and the undersides of
the bolt heads, then refit them. Note:Use the
old bolts for this step (save the new bolts for
final refitting).
12Tighten the main bearing cap bolts, in
three steps, to the torque listed in this
Chapter’s Specifications. Don’t rotate the
crankshaft at any time during this operation!
13Remove the bolts and carefully lift off the
main bearing caps or cap assembly. Keep
them in order. Don’t disturb the Plastigauge or
rotate the crankshaft. If any of the main
bearing caps are difficult to remove, tap them
gently from side-to-side with a soft-face
hammer to loosen them.14Compare the width of the crushed
Plastigauge on each journal to the scale printed
on the Plastigauge envelope to obtain the main
bearing oil clearance (see illustration). Check
the Specifications to make sure it’s correct.
15If the clearance is not as specified, the
bearing inserts may be the wrong size (which
means different ones will be required - see
Section 20). Before deciding that different
inserts are needed, make sure that no dirt or
oil was between the bearing inserts and the
caps or engine block when the clearance was
measured. If the Plastigauge is noticeably
wider at one end than the other, the journal
may be tapered (see Section 19).
16Carefully scrape all traces of the
Plastigauge material off the main bearing
journals and/or the bearing faces. Don’t nick
or scratch the bearing faces.
Final crankshaft refitting
17Carefully lift the crankshaft out of the
engine. Clean the bearing faces in the engine
block, then apply a thin, uniform layer of clean
moly-base grease or engine assembly lube to
each of the bearing surfaces. Coat the thrust
washers as well.
18Lubricate the crankshaft surfaces that
contact the oil seals with moly-base grease,
engine assembly lube or clean engine oil.
19Make sure the crankshaft journals are
clean, then lay the crankshaft back in place in
the engine block. Clean the faces of the
bearings in the main bearing caps, then apply
lubricant to them. Refit the main bearing caps
in their respective positions with the arrows
pointing toward the front of the engine. Note:
Be sure to refit the thrust washers (lubricated)
with the number 4 main journal.The upper
(block side) thrust washers can be rotated into
position around the crankshaft with the
crankshaft installed in the engine block, with
the thrust washer grooves facing OUT. The
lower thrust washers should be placed on the
main bearing caps with their grooves OUT.
20For the final assembly, use only new
bolts, for both the main bearings and the
2B•16 Engine removal and overhaul procedures
23.10 Lay the Plastigauge strips on the
main bearing journals, parallel to the
crankshaft centreline
23.14 Compare the width of the crushed
Plastigauge to the scale on the envelope to
determine the main bearing oil clearance
(always take the measurement at the
widest point of the Plastigauge). Be sure to
use the correct scale - imperial and metric
scales are included
3261 Jaguar XJ6
22.12 Refit the compression rings with a
ring expander - the mark must face up

connecting rods. Apply a light coat of oil to
the bolt threads and the under sides of the
bolt heads, then refit them. Tighten all main
bearing cap bolts to the torque listed in this
Chapter’s Specifications, starting in the centre
and working out to the ends.
21Rotate the crankshaft a number of times
by hand to check for any obvious binding.
22Check the crankshaft endplay with a
feeler gauge or a dial indicator as described in
Section 14. The endplay should be correct if
the crankshaft thrust faces aren’t worn or
damaged and new thrust washers have been
installed. Note:If the end-play is too great,
even with the new thrust bearings, oversized
thrust bearings are available. There are two
sizes, 0.005-inch and 0.010-inch oversize.
23Refit a new rear main oil seal, then bolt the
retainer to the engine block (see Section 24).
24 Rear main oil seal refitting
2
1The crankshaft must be installed first and
the main bearing caps bolted in place, then
the new seal should be installed in the retainer
and the retainer bolted to the engine block.
2Check the seal contact surface on the
crankshaft very carefully for scratches and
nicks that could damage the new seal lip and
cause oil leaks. If the crankshaft is damaged,
the only alternative is a new or different
crankshaft.
3Refer to Part A of this Chapter for refitting
of the new rear seal, using the plastic
alignment tool supplied with the engine
overhaul gasket set.
25 Pistons/connecting rods-
refitting and big-end bearing
oil clearance check
3
1Before refitting the piston/connecting rod
assemblies, the cylinder walls must be
perfectly clean, the top edge of each cylinder
must be chamfered, and the crankshaft must
be in place.
2Remove the cap from the end of the
number one connecting rod (refer to the
marks made during removal). Remove the
original bearing inserts and wipe the bearing
surfaces of the connecting rod and cap with a
clean, lint-free cloth. They must be kept
spotlessly clean.
Big-end bearing
oil clearance check
3Clean the back side of the new upper
bearing insert, then lay it in place in the
connecting rod. Make sure the tab on the
bearing fits into the recess in the rod so the oil
holes line up. Don’t hammer the bearing insert
into place and be very careful not to nick or
gouge the bearing face. Don’t lubricate the
bearing at this time.4Clean the back side of the other bearing
insert and refit it in the rod cap. Again, make
sure the tab on the bearing fits into the recess
in the cap, and don’t apply any lubricant. It’s
critically important that the mating surfaces of
the bearing and connecting rod are perfectly
clean and oil free when they’re assembled.
5Position the piston ring gaps at staggered
intervals around the piston (see illustration).
6Slip a section of plastic or rubber hose over
each connecting rod cap bolt.
7Lubricate the piston and rings with clean
engine oil and attach a piston ring compressor
to the piston. Leave the skirt protruding about
1/4-inch to guide the piston into the cylinder.
The rings must be compressed until they’re
flush with the piston.
8Rotate the crankshaft until the number one
connecting rod journal is at BDC (bottom
dead centre) and apply a coat of engine oil to
the cylinder wall.
9With the word FRONT (or the arrow) on top
of the piston facing the front of the engine
(see illustration), gently insert the piston/
connecting rod assembly into the number one
cylinder bore and rest the bottom edge of the
ring compressor on the engine block.
10Tap the top edge of the ring compressor
to make sure it’s contacting the engine block
around its entire circumference.11Gently tap on the top of the piston with
the end of a wooden hammer handle (see
illustration) while guiding the end of the
connecting rod into place on the crankshaft
journal. The piston rings may try to pop out of
the ring compressor just before entering the
cylinder bore, so keep some downward
pressure on the ring compressor. Work
slowly, and if any resistance is felt as the
piston enters the cylinder, stop immediately.
Find out what’s hanging up and fix it before
proceeding.
Caution: Do not, for any reason, force the
piston into the cylinder - you might break a
ring and/or the piston.
12Once the piston/connecting rod assembly
is installed, the big-end bearing oil clearance
must be checked before the rod cap is
permanently bolted in place.
13Cut a piece of the appropriate size
Plastigauge slightly shorter than the width of
the big-end bearing and lay it in place on the
number one connecting rod journal, parallel
with the journal axis (see illustration).
14Clean the connecting rod cap bearing
face, remove the protective hoses from the
connecting rod bolts and refit the rod cap.
Make sure the mating mark on the cap is on
the same side as the mark on the connecting
rod. Check the cap to make sure the front
mark is facing the timing chain of the engine.
15Apply a light coat of oil to the under sides
of the nuts, then refit and tighten them to the
torque listed in this Chapter’s Specifications,
Engine removal and overhaul procedures 2B•17
2B
25.13 Lay the Plastigauge strips on each
big-end bearing journal, parallel to the
crankshaft centreline
3261 Jaguar XJ6
25.5 Stagger the ring end gaps around the
piston as shown25.9 Pistons must be installed with the
arrow (right arrow) or FRONT facing the
front of the engine - left arrow indicates
piston size letter
25.11 The piston can be driven (gently)
into the cylinder bore with the end of a
wooden or plastic hammer handle
A Oil ring rail gaps
B Second compression ring gap
C Oil ring spacer gap
D Top compression ring gap

working up to it in three steps. Note:Use the
old bolts for this step (save the new bolts for
final refitting).Use a thin-wall socket to avoid
erroneous torque readings that can result if
the socket is wedged between the rod cap
and nut. If the socket tends to wedge itself
between the nut and the cap, lift up on it
slightly until it no longer contacts the cap. Do
not rotate the crankshaft at any time during
this operation.
16Remove the nuts and detach the rod cap,
being careful not to disturb the Plastigauge.
17Compare the width of the crushed
Plastigauge to the scale printed on the
envelope to obtain the oil clearance (see
illustration). Compare it to this Chapter’s
Specifications to make sure the clearance is
correct.
18If the clearance is not as specified, the
bearing inserts may be the wrong size (which
means different ones will be required). Before
deciding that different inserts are needed,
make sure that no dirt or oil was between the
bearing inserts and the connecting rod or cap
when the clearance was measured. Also,
recheck the journal diameter. If the Plastigauge
was wider at one end than the other, the journal
may be tapered (refer to Section 19).
Final connecting rod refitting
19Carefully scrape all traces of the
Plastigauge material off the rod journal and/or
bearing face. Be very careful not to scratchthe bearing, use your fingernail or the edge of
a credit card to remove the Plastigauge.
20Make sure the bearing faces are perfectly
clean, then apply a uniform layer of clean
moly-base grease or engine assembly lube to
both of them. You’ll have to push the piston
higher into the cylinder to expose the face of
the bearing insert in the connecting rod, be
sure to slip the protective hoses over the
connecting rod bolts first.
21At this time, remove the original
connecting rod bolts/nuts and replace them
with new bolts/nuts. They are of a design
which requires they be used only once. The
old ones are OK for Plastigauge checking, but
for final assembly use only new connecting
rod bolts/nuts. Refit the rod cap and tighten
the nuts to the torque listed in this Chapter’s
Specifications. Again, work up to the torque in
three steps.
22Repeat the entire procedure for the
remaining pistons/connecting rod assemblies.
23The important points to remember are:
a) Keep the back sides of the bearing inserts
and the insides of the connecting rods and
caps perfectly clean during assembly..
b) Make sure you have the correct piston/
connecting rod assembly for each
cylinder.
c) The dimple on the piston must face the
front of the engine.
d) Lubricate the cylinder walls with clean oil.
e) Lubricate the bearing faces when refitting
the rod caps after the oil clearance has
been checked.
24After all the piston/connecting rod
assemblies have been properly installed,
rotate the crankshaft a number of times by
hand to check for any obvious binding.
25As a final step, the connecting rod
endplay must be checked. Refer to Section 13
for this procedure.
26Compare the measured endplay to this
Chapter’s Specifications to make sure it’s
correct. If it was correct before dismantling
and the original crankshaft and connecting
rods were reinstalled, it should still be right.
However, if new connecting rods or a new
crankshaft were installed, the endplay may beinadequate. If so, the connecting rods will
have to be removed and taken to an
automotive machine workshop for resizing.
26 Initial start-up
and running-in after overhaul
1
Warning: Have a suitable fire
extinguisher handy when starting
the engine for the first time.
1Once the engine has been installed in the
vehicle, double-check the engine oil and
coolant levels.
2With the spark plugs out of the engine and
the ignition system and fuel pump disabled,
crank the engine until oil pressure registers on
the gauge or the light goes out.
3Refit the spark plugs, hook up the plug
leads and restore the ignition system and fuel
pump functions.
4Start the engine. It may take a few
moments for the fuel system to build up
pressure, but the engine should start without
a great deal of effort.
5After the engine starts, it should be allowed
to warm up to normal operating temperature.
While the engine is warming up, make a
thorough check for fuel, oil and coolant leaks.
6Shut the engine off and recheck the engine
oil and coolant levels.
7Drive the vehicle to an area with no traffic,
accelerate from 30 to 50 mph, then allow the
vehicle to slow to 30 mph with the throttle
closed. Repeat the procedure 10 or 12 times.
This will load the piston rings and cause them
to seat properly against the cylinder walls.
Check again for oil and coolant leaks.
8Drive the vehicle gently for the first
500 miles (no sustained high speeds) and
keep a constant check on the oil level. It is not
unusual for an engine to use oil during the
running-in period.
9At approximately 500 to 600 miles, change
the oil and filter.
10For the next few hundred miles, drive the
vehicle normally. Do not pamper it or abuse it.
11After 2000 miles, change the oil and filter
again and consider the engine run-in.
2B•18 Engine removal and overhaul procedures
25.17 Measure the width of the crushed
Plastigauge to determine the big-end
bearing oil clearance
3261 Jaguar XJ6